XPath 2.0
XPath 2.0 is a query language for selecting nodes from XML documents, extending the original XPath 1.0 with enhanced data types, functions, and expressions. It is part of the XSLT 2.0 and XQuery 1.0 specifications, providing powerful capabilities for navigating and processing XML data. Developers use it to extract specific information, perform calculations, and transform XML structures in applications like web services, configuration files, and data interchange.
Developers should learn XPath 2.0 when working with XML-based systems that require complex queries, such as in data integration, document processing, or SOAP/XML web services. It is essential for tasks like filtering nodes with conditional logic, handling sequences, and using built-in functions for string manipulation and date arithmetic. For example, it's used in XSLT transformations to generate HTML from XML or in XQuery to query XML databases efficiently.